U.S. patent application number 10/152445 was filed with the patent office on 2003-11-27 for liquid hand dishwashing detergent.
Invention is credited to Manske, Scott D..
Application Number | 20030220215 10/152445 |
Document ID | / |
Family ID | 29400518 |
Filed Date | 2003-11-27 |
United States Patent
Application |
20030220215 |
Kind Code |
A1 |
Manske, Scott D. |
November 27, 2003 |
Liquid hand dishwashing detergent
Abstract
The invention relates to a class of detergent compositions for
use in hand dishwashing that provides excellent performance as
measured by persistence of foam in the presence of oily and fatty
types of soils. Testing based on escalating amounts of such soils
to the extinction of the foam showed surprising advantage of hand
dishwashing composition comprising at least two anionic surfactants
and a polyethylene glycol and being essentially free of alkyl
polyglucosides.
Inventors: |
Manske, Scott D.; (Davidson,
NC) |
Correspondence
Address: |
CLARIANT CORPORATION
INTELLECTUAL PROPERTY DEPARTMENT
4000 MONROE ROAD
CHARLOTTE
NC
28205
US
|
Family ID: |
29400518 |
Appl. No.: |
10/152445 |
Filed: |
May 21, 2002 |
Current U.S.
Class: |
510/220 ;
510/424; 510/426; 510/470; 510/490 |
Current CPC
Class: |
C11D 1/143 20130101;
C11D 1/90 20130101; C11D 1/37 20130101; C11D 1/146 20130101; C11D
1/75 20130101; C11D 1/83 20130101; C11D 1/94 20130101; C11D 3/2068
20130101 |
Class at
Publication: |
510/220 ;
510/424; 510/426; 510/470; 510/490 |
International
Class: |
C11D 017/00 |
Claims
I claim:
1. A dishwashing detergent composition comprising an anionic
surfactant mixture containing at least two different anionic
surfactants, a polyethylene glycol, water, and a phase stabilizer
selected from the group consisting of a hydrotrope, an inorganic
salt, and mixtures thereof, wherein said dishwashing detergent
composition is essentially free of alkyl polyglucoside surfactants
and the polyethylene glycol having a molecular weight ranging from
about 400 to about 1000 comprises from about 0.5 to 10 weight
percent of the dishwashing detergent.
2. The dishwashing detergent of claim 1 wherein the anionic
surfactant mixture comprising at least two different surfactants
are selected from the group consisting of an alkane sulfonate, an
alkyl benzene sulfonate, an alpha olefin sulfonate, an alkyl
sulfate, an alkyl ether sulfate, an alkyl ester sulfonate, and
mixtures thereof.
3. The dishwashing detergent of claim 1 wherein the inorganic salt
is selected from the group consisting of magnesium chloride,
magnesium sulfate, and mixtures thereof.
4. The dishwashing detergent of claim 1 wherein the hydrotrope is
selected from the group consisting of ethanol, isopropanol, sodium
xylene sulfonate, propylene glycol, dipropylene glycol, sodium
cumene sulfonate, and mixtures thereof.
5. The dishwashing detergent of claim 1 further comprising a foam
stabilizing surfactant selected from the group consisting of a
betaine compound, an amine oxide, an alkanolamide compound, and
mixtures thereof.
6. The dishwashing detergent of claim 5 wherein the betaine
compound is selected from the group consisting of coco
acylamidopropyldimethyl betaine; hexadecyl dimethyl betaine;
C.sub.12-C.sub.14 acylamidopropylbetaine; C.sub.12-C.sub.18
acylamidohexyldiethyl betaine; 4-(C.sub.14-C.sub.16
acylmethylamidodiethylammonio)-1-carboxybutane; C.sub.16-C.sub.18
acylamidodimethylbetaine; C.sub.12-C.sub.16
acylamidopentanediethyl-betaine; C.sub.12-C.sub.16
acylmethyl-amidodimethylbetaine, coco amidopropyl betaine, and
mixtures thereof.
7. The dishwashing detergent of claim 1 wherein the anionic mixture
comprises a first anionic surfactant comprised of an alkyl
sulfonate and a second anionic surfactant selected from the group
consisting of alpha olefin sulfonate, alkyl ether sulfate, alkyl
sulfate, alkyl benzene sulfonate, alkyl ester sulfonate, and
mixtures thereof.
8. The dishwashing detergent of claim 7 wherein the anionic
surfactant mixture comprises 6-30 wt-% of a first surfactant and
6-30 wt-% of a second anionic surfactant.
9. The dishwashing detergent of claim 1 wherein the polyethylene
glycol comprises a molecular weight from about 400 to about
800.
10. The dishwashing detergent of claim 1 wherein the polyethylene
glycol comprises a molecular weight from about 400 to about
600.
11. The dishwashing detergent of claim 7 wherein a ratio of the
first anionic surfactant to the second anionic surfactant ranges
from about 5:1 to 1:5.
12. The dishwashing detergent of claim 1 wherein a total surfactant
level ranges from about 15 to about 60 weight percent.
13. The dishwashing detergent of claim 1 wherein a total surfactant
level ranges from about 20 to about 50 weight percent.
14. The dishwashing detergent of claim 1 wherein the dishwashing
detergent comprises less than about 0.005 wt-% alkyl polyglucoside
surfactants.
15. The dishwashing detergent of claim 5 wherein the amine oxide is
selected from the group consisting of C.sub.10-C.sub.18 alkyl
dimethyl amine oxides, C.sub.8-C.sub.12 alkoxy ethyl dihydroxyethyl
amine oxides, alkyl amidopropyl amine oxide, and mixtures
thereof.
16. The dishwashing detergent of claim 5 wherein the alkanoamide
compound is selected from the group consisting of alkyl monoalkanol
amide, alkyl dialkanol amide and mixtures thereof.
17. The dishwashing detergent of claim 5 wherein a ratio of the
foam stabilizing surfactant to the anionic surfactant mixture
comprises about 1:2 or less.
18. The dishwashing detergent of claim 7 wherein a ratio of the
first anionic surfactant to the second anionic surfactant ranges
from about 3:1 to 1:3.
19. The dishwashing detergent of claim 7 wherein a ratio of the
first anionic surfactant to the second anionic surfactant ranges
from about 1.5:1 to 1:1.5.
20. A liquid dishwashing detergent consisting essentially of:
water; about 5 to 30% by weight of an anionic surfactant; about 5
to 30% by weight of a co-anionic surfactant; about 0.5 to 10% by
weight of polyethylene glycol; about 0 to 15% by weight of a foam
stabilizing surfactant; and, about 0 to 15% by weight of optional
ingredients; wherein the polyethylene glycol has a molecular weight
ranging from about 400 to about 1000.
21. The liquid dishwashing detergent of claim 20 wherein the
anionic surfactant comprises an alkyl sulfonate and the co-anionic
surfactant is selected from the group consisting of an alpha olefin
sulfonate, an alkyl ether sulfate, and mixtures thereof with the
proviso that a ratio of the anionic surfactant to the co-anionic
surfactant is between about 0.5 and less than 1.0.
22. The liquid dishwashing detergent of claim 20 wherein the foam
stabilizing surfactant comprises a betaine compound and/or an amine
oxide.
23. The dishwashing detergent of claim 20 wherein the optional
ingredients are selected from the group consisting of hydrotropes,
perfumes, colorants, pH adjusting agents, preservatives, biocidal
agents, inorganic salts, opacifiers, viscosity modifiers, and
mixtures thereof.
Description
FIELD OF INVENTION
[0001] The present invention relates to a liquid detergent
formulation for the hand washing of dishes. More particularly, the
present invention relates to a detergent formulation for the hand
washing of dishes where the persistence of foam in the presence of
oily, fatty types of soils is critical to the performance of the
detergent.
BACKGROUND OF INVENTION
[0002] Liquid hand dishwashing detergent or alternatively referred
to as light-duty liquid detergent (LDL) formulations for the
cleaning of kitchen surfaces are well known. Kitchen surfaces
include counter tops, stove tops, dishes and any other hard surface
commonly found in kitchen environments. The term "dishes" includes
any utensils involved in food preparation or consumption. Kitchen
surfaces, particularly dishes, must be washed free of food
residues, greases, proteins, starches, gums, dyes, oils and burnt
organic residues. As the term "hand dishwashing" implies, the
products typically come into contact with both these hard surfaces
to be cleaned and the skin of the person using the product.
[0003] Most of the consumer accepted formulations for cleaning
dishes with hand dishwashing detergents include anionic surfactants
as the primary cleaning ingredients and mildness enhancing, foam
stabilizing surfactants such as amine oxides, betaines, and
alkanolamides as the secondary surfactants. A significant number of
formulations will also include conventional nonionic surfactants
(e.g. alcohol ethoxylate, alkyl phenol ethoxylate) and/or specialty
nonionic surfactants (i.e. alkyl polyglucoside) to provide the
benefits of a mixed active system.
[0004] The anionic surfactants in such formulations generally
provide the typical high foaming characteristics associated with
dishwashing formulations. The foam stabilizing surfactants
typically provide the formulation with enhanced product mildness to
contacted skin during hand dishwashing and enhanced performance
robustness to higher water hardness and to removed soil. This
enhanced product performance robustness is typically shown by high
levels of foam over a wide range of water hardness levels combined
with extended foam persistence during the washing process as more
and more soils are deterged into the wash solution.
[0005] Foam persistence in the presence of increasing amounts of
removed soils throughout the washing session is arguably the most
important cleaning efficacy signal relied on by consumers. The hand
dishwashing detergent industry uses the laboratory Miniplate Test
as the key laboratory appraisal method for assessing this most
important performance criterion and to quantify the performance
quality of liquid hand dishwashing detergent formulations.
[0006] U.S. Pat. No. 5,968,890 B1 discloses a liquid detergent
composition for cleansing the skin and hair and comprising a
synthetic anionic surfactant, and an amphoteric surfactant and a
polyethylene glycol for improved lather.
[0007] U.S. Pat. No. 6,268,330 B1 discloses an acidic light duty
liquid detergent which is mild to the skin which can be in the form
of a clear microemulsion and comprises a sulfate and a sulfonate
anionic surfactant and a hydroxy aliphatic acid.
[0008] U.S. Pat. No. 6,251,844 B1 discloses an acidic light duty
detergent with desirable high foaming and cleaning properties which
kills bacteria and is mild to the skin. The light duty liquid
detergent comprises an anionic surfactant, zwitterionic surfactant,
polyethylene glycol, and a hydroxy acid. The anionic surfactant is
present from 10-52 wt-% as a mixture of an alkali metal salt of an
anionic sulfonate surfactant and an alkali metal salt of a
C.sub.8-C.sub.18 ethoxylated alkyl ether sulfate or
C.sub.8-C.sub.18 alkyl ether sulfate having a weight ratio of
sulfonate surfactant to sulfate surfactant of 20 to 1:1. The
zwitterionic surfactant is a water soluble betaine. The light duty
liquid detergent further requires a magnesium salt as an essential
ingredient to improve overall product performance.
[0009] U.S. Pat. No. 6,339,057 B1 discloses a high foaming
detergent formulation having a non-ionic base. The reference points
out a problem of incompatibility between anionic surfactants and
cationic quaternary antimicrobial and the problem that non-ionic
surfactants do not normally provide significant foaming capability
to liquid formulations.
[0010] U.S. Pat. No. 5,955,411 discloses a high foaming light duty
liquid detergent having antibacterial properties containing alkyl
polyglucoside and polyethylene glycol in order to improve the
viscosity of the detergent composition and to improve the flash
foam point of the composition.
[0011] U.S. Pat. Nos. 5,696,073 B1, 5,700,773 B1, 5,834,417 B1,
5,853,743 B1, 5,854,195 B1, and 5,856,293 B1 disclose a series of
light duty liquid cleaning compositions comprising anionic
surfactants, specialty co-surfactants, polyethylene glycol,
inorganic salts, hydrotroping agents, and an alkyl polyglucoside
surfactant, wherein the alkyl polyglucoside is incorporated to
provide mildness to human skin.
[0012] U.S. Pat. No. 5,998,355 B1 discloses a liquid dishwashing
detergent that exhibits increased viscosity, better dissolution
rate, and improved cleaning performance in hard water. The liquid
dishwashing detergent comprises from about 1 to 90 percent of an
anionic surfactant and from about 1 to 30 percent of a solvent
hydrotrope selected from the group consisting of alkoxylated
glycerides, alkoxylated glycerines, esters of alkoxylated
glycerines, alkoxylated fatty acids, esters of glycerine,
polyglycerol esters and combinations thereof.
[0013] It is an objective of the present invention to provide a
light duty liquid detergent which provides improved detergency in
hard water and in the presence of oily and fatty types of
soils.
[0014] It is an objective to produce a light duty liquid detergent
which exhibits foam persistence in the presence of oily and fatty
types of soils.
[0015] It is an objective of the present invention to provide an
improved light duty liquid detergent at a lower cost by eliminating
exotic materials such as alkyl polyglucoside (APG) surfactants.
SUMMARY OF THE INVENTION
[0016] The invention relates to a class of compositions for use in
light duty liquid, or liquid hand dishwashing detergents which
provide excellent performance as measured by persistence of foam in
the presence of oily and fatty types of soils. Testing of product
performance--based on the stability of foam in the presence of
escalating amounts of fatty or oily soils as indicated by the
extinction of the foam--showed surprising advantage of the hand
dishwashing detergent composition which is essentially free of
alkyl polyglucoside, wherein the hand dishwashing detergent
comprises at least two different anionic surfactants and a
polyethylene glycol.
[0017] In one embodiment, the present invention is a liquid
dishwashing detergent composition which comprises water, an anionic
surfactant mixture containing at least two different anionic
surfactants, a polyethylene glycol, and a hydrotrope and/or an
inorganic magnesium salt, wherein the liquid dishwashing detergent
is essentially free of alkyl polyglucoside (APG) surfactants. The
formulation includes a phase stabilizer selected from the group
consisting of a hydrotrope, an inorganic salt, and mixtures
thereof. The polyethylene glycol employed in the dishwashing
detergent formulation of the present invention comprises from about
0.5 to 10 weight percent of the dishwashing detergent and has a
molecular weight ranging from about 400 to about 1000.
[0018] In another embodiment, the liquid dishwashing detergent
consists essentially of: water;
[0019] about 5 to 30% by weight of an anionic surfactant;
[0020] about 5 to 30% by weight of a co-anionic surfactant;
[0021] about 0.5 to 10% by weight of polyethylene glycol;
[0022] about 0 to 15% by weight of a foam stabilizing surfactant;
and,
[0023] about 0 to 15% by weight of optional ingredients;
[0024] wherein the polyethylene glycol has a molecular weight
ranging from about 400 to about 1000, with the proviso that the
liquid dishwashing detergent be essentially free of alkyl
polyglucosides. The optional ingredients are selected from the
group consisting of hydrotropes, perfumes, colorants, pH adjusting
agents, opacifiers, biocidal agents, preservatives, inorganic
salts, viscosity modifiers, and mixtures thereof.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Applicant discovered that the combination of at least two
different anionic surfactants, a foam stabilizing surfactant, and
polyethylene glycol resulted in surprisingly improved detergency
performance, as measured by the well-known mini-plate test in water
of varying hardness, than would have been predicted by just the
addition of polyethylene glycol to liquid anionic dish washing
detergent formulations with a single anionic surfactant either with
or without a foam stabilizing surfactant. The instant invention is
characterized in that the formulation of the present invention
contains essentially no alkyl polyglucosides. By the term
essentially no alkyl polyglucosides, it is meant that the
dishwashing detergent contains less than about 0.005 weight percent
alkyl polyglucosides. By the term alkyl polyglucosides as used
herein, alkyl polyglucosides or alkyl polyglucoside surfactants
include alkyl polysaccharides, alkyl monosaccharides and admixtures
thereof. Examples include: C.sub.5-C.sub.17
acyl-N--(C.sub.1-C.sub.4 alkyl) and --N--(C.sub.1-C.sub.2
hydroxyalkyl)glucamine sulfates, and sulfates of alkyl
polysaccharides, such as sulfates of alkyl polyglucoside. The
characterization of alkyl polyglucosides as disclosed in U.S. Pat.
Nos. 5,834,417 B1 , 5,853,743 B1, and 5,854,195 B1 are hereby
incorporated by reference.
[0026] Anionic Surfactants
[0027] Anionic sulfonate surfactants suitable for use herein
include the salts of C.sub.5-C.sub.20 linear alkylbenzene
sulfonates, alkyl ester sulfonates, C.sub.6-C.sub.22 primary or
secondary alkane sulfonates, C.sub.6-C.sub.24 olefin sulfonates,
sulfonated polycarboxylic acids, alkyl glycerol sulfonates, fatty
acyl glycerol sulfonates, fatty oleyl glycerol sulfonates, and any
mixtures thereof.
[0028] Anionic sulfate surfactants suitable for use in the
compositions of the invention include linear and branched primary
and secondary alkyl sulfates, alkyl ethoxysulfates, fatty oleoyl
glycerol sulfates, and alkyl phenol ethylene oxide ether
sulfates.
[0029] Suitable anionic carboxylate surfactants include alkyl
ethoxy carboxylates, alkyl polyethoxy polycarboxylate surfactants
and soaps ("alkyl carboxyls").
[0030] An example of a preferred anionic surfactant would be the
sodium salt of secondary alkane sulfonate commercially available
under the tradename of Hostapur.RTM. SAS (Clariant Corporation,
Charlotte, N.C.).
[0031] Polyethylene Glycol
[0032] It was discovered that the molecular weight of the
polyethylene glycol had a significant impact on the detergent
performance. Polyethylene glycols having a molecular weight ranging
between about 400 and about 1000 provided the greatest benefit. The
polyethylene glycol used in the instant composition has a molecular
weight of 200 to 1,500, wherein the polyethylene glycol has the
structure
HO(CH.sub.2CH.sub.2 O).sub.n--H
[0033] wherein n is 4 to 25. The concentration of the polyethylene
glycol in the instant composition is 0.5 to 10 wt. %, more
preferably 0.75 wt. % to 6 wt. %. Preferably, the molecular weight
of the polyethylene glycol ranges from about 400 to about 1500,
more preferably, the molecular weight of the polyethylene glycol
ranges between about 400 and about 1000, and most preferably, the
molecular weight of the polyethylene glycol ranges between about
400 and about 800.
[0034] Water
[0035] The final ingredient in the inventive compositions is water.
The proportion of water in the compositions generally is in the
range of 35% to 85%, preferably 50% to 80% by weight of the usual
composition.
[0036] Amine Oxide
[0037] Amine oxides useful in the present invention include
long-chain alkyl amine oxides, ie., those compounds having the
formula
[0038] R.sup.3(OR .sup.4).sub.x--(NO)--(R.sup.5).sub.2
[0039] wherein R.sup.3 is selected from an alkyl, hydroxyalkyl,
acylamidopropyl and alkyl phenyl group, or mixtures thereof,
containing from 8 to 26 carbon atoms, preferably 8 to 16 carbon
atoms; R.sup.4 is an alkylene or hydroxyalkylene group containing
from 2 to 3 carbon atoms, preferably 2 carbon atoms, or mixtures
thereof; x is from 0 to 3, preferably 0; and each R.sup.5 is an
alkyl or hydroxyalkyl group containing from 1 to 3, preferably from
1 to 2 carbon atoms, or a polyethylene oxide group containing from
1 to 3, preferably 1, ethylene oxide groups. The R.sup.5 groups can
be attached to each other, e.g., through an oxygen or nitrogen
atom, to form a ring structure.
[0040] These amine oxide surfactants in particular include
C.sub.10-C.sub.18 alkyl dimethyl amine oxides and C.sub.8-C.sub.12
alkoxy ethyl dihydroxyethyl amine oxides and alkyl amido propyl
amine oxide. Examples of such materials include dimethyloctylamine
oxide, diethyldecylamine oxide, bis-(2-hydroxyethyl)dodecylamine
oxide, dimethyldodecylamine oxide, dodecylamidopropyl dimethylamine
oxide and dimethyl-2-hydroxyoctadecylamine oxide. Preferred are
C.sub.10-C.sub.18 alkyl dimethylamine oxide, and C.sub.10-C.sub.18
acylamido alkyl dimethylamine oxide.
[0041] Betaine
[0042] The betaines useful in the present invention are those
compounds having the formula R(R.sup.1).sub.2 N.sup.+ R.sup.2
COO.sup.- wherein R is a C.sub.6-C.sub.18 hydrocarbyl group,
preferably C.sub.10-C.sub.16 alkyl group, each R.sup.1 is typically
C.sub.1-C.sub.3, alkyl, preferably methyl, and R.sup.2 is a
C.sub.1-C.sub.5 hydrocarbyl group, preferably a C.sub.1-C.sub.5
alkylene group, more preferably a C.sub.1-C.sub.2 alkylene group.
Examples of suitable betaines include coconut
acylamidopropyldimethyl betaine; hexadecyl dimethyl betaine;
C.sub.12-C.sub.14 acylamidopropylbetaine; C.sub.12-C.sub.18
acylamidohexyldiethyl betaine; 4-[C.sub.14-C.sub.16
acylmethylamidodiethylammonio]-1-carboxybutane; C.sub.16-C.sub.18
acylamidodimethylbetaine; C.sub.12-C.sub.16
acylamidopentanediethyl-betai- ne; C.sub.12-C.sub.16
acylmethyl-amidodimethylbetaine, and coco amidopropyl betaine.
Preferred betaines are C.sub.12-C.sub.18 dimethylamoniohexanoate
and the C.sub.10-C.sub.18 acylamidopropane (or ethane) dimethyl (or
diethyl) betaines. Also included are sulfobetaines (sultaines) of
formula R(R.sub.1).sub.2 N+R.sub.2 SO.sub.3--, wherein R is a
C.sub.6-C.sub.18 Hydrocarbyl group, preferably a C.sub.10-C.sub.16
alkyl group, more preferably a C.sub.12-C.sub.13 alkyl group; each
R.sub.1 is typically C.sub.1-C.sub.3 alkyl, preferably methyl and
R.sub.2 is a C.sub.1-C.sub.6 hydrocarbyl group, preferably a
C.sub.1-C.sub.3 alkylene or, preferably, hydroxyalkylene group.
Examples of suitable sultaines are C.sub.12-C.sub.14
dihydroxyethylammonio propane sulfonate, and
C.sub..sub.16-C.sub..sub.18 dimethylammonio hexane sulfonate, with
C.sub.12-C.sub.14 amido propyl ammonio-2-hydroxypropyl sultaine
being preferred.
[0043] Alkanolamide Compounds
[0044] The present formulation can include an alkanolamide compound
such as an alkyl monoalkanol amide, an alkyl dialkanol amide, and
mixtures thereof.
[0045] Hydrotrope
[0046] The formulation of the present invention can include a
hydrotrope selected from the group consisting of ethanol,
isopropanol, sodium xylene sulfonate, propylene glycol, dipropylene
glycol, sodium cumene sulfonate and mixtures thereof.
[0047] Inorganic Salt
[0048] The formulation of the present invention can include an
inorganic or organic salt or oxide of a multivalent cation,
particularly Mg.sup.++ which has phase stabilization properties.
The multivalent cation salt or oxide provides several benefits
including improved cleaning performance in dilute usage,
particularly in soft water areas, and minimized amounts of perfume
required to obtain the microemulsion state. Magnesium sulfate,
either anhydrous or hydrated (e.g., heptahydrate), is especially
preferred as the magnesium salt. Good results also have been
reported with magnesium oxide, magnesium chloride, magnesium
acetate, magnesium propionate and magnesium hydroxide. These
magnesium salts can be used with formulations at neutral or acidic
pH since magnesium hydroxide will not precipitate at these pH
levels.
[0049] Although magnesium is the preferred multivalent cation from
which the salts (inclusive of the oxide and hydroxide) are formed,
other polyvalent metal ions also can be used provided that their
salts are nontoxic and are soluble in the aqueous phase of the
system at the desired pH level.
[0050] The liquid cleaning composition of this invention may, if
desired, also contain other optional components either to provide
additional effect or to make the product more attractive to the
consumer. The following are mentioned by way of example: Colorants
or dyes in amounts up to 0.5% by weight; preservatives or
antioxidizing agents, such as formalin, 5-bromo-5-nitro-dioxan-1,3;
5-chloro-2-methyl-4-isothaliazolin-- 3-one,
2,6-di-tert.butyl-p-cresol, etc., in amounts up to 2% by weight;
and pH adjusting agents, such as sulfuric acid or sodium hydroxide,
as needed. Furthermore, if opaque compositions are desired, up to
4% by weight of an opacifier may be added. Preferably, the optional
ingredients are selected from the group consisting of hydrotropes,
perfumes, colorants, pH adjusting agents, preservatives, biocidal
agents, inorganic salts, opacifiers, viscosity modifiers, and
mixtures thereof
[0051] In the present formulation, it was discovered that certain
parameters were required to achieve the benefits of the invention.
The total surfactant level in the detergent formulation includes
all surfactants in the detergent for example, the anionics, any
non-ionic and any amphoteric surfactants. The polyethylene glycol
(PEG) is not considered a surfactant. Preferably, the hand
dishwashing composition will comprise from about 15 to about 60
weight percent total surfactant, more preferably the hand
dishwashing detergent comprises from about 20 to about 50 weight
percent total surfactant, and most preferably, the hand dishwashing
detergent comprises from about 20 to about 40 weight percent total
surfactant. More particularly, the ratio of the first anionic
surfactant to the second anionic surfactant comprises between about
0.5 and less than 1.0. The ratio of the foam stabilizing surfactant
to the anionic surfactant mixture should comprise about 1:2 or
less.
[0052] In the instant invention, detergent formulations were sought
which comprised anionic surfactants that provide persistence of
foam in the presence of oily and fatty types of soils. Testing of
product performance--based on the stability of foam in the presence
of escalating amounts of fatty or oily soils as indicated by the
extinction of the foam--showed surprising advantage of liquid hand
dishwashing detergent compositions comprising at least two
different anionic surfactants and a polyethylene glycol. In one set
of experiments, dishwashing detergent formulations having between
about 38 and about 42 weight percent anionic surfactants comprising
both a secondary alkane sulfonate and an alkyl ether sulfate in
approximately equal proportions, and a foam stabilizing surfactant
such as amine oxide or coco amidopropyl betaine were tested with
polyethylene glycols of increasing molecular weight. It was found
that the addition of polyethylene glycols having a molecular weight
ranging between about 400 to about 800 exhibited significant
improvement in performance as measured by the well-known Mini Plate
test in water having a hardness of about 150 ppm. At the 150 ppm
level of hardness, the performance of formulations with
polyethylene glycol having a molecular weight ranging from 400 to
800, improved between 20 and 40 percent over formulations having no
polyethylene glycol or having similar concentrations of
polyethylene glycol with a molecular weight greater than 800. At
hardness levels of about 300 ppm, adding polyethylene glycol
resulted in a similar relative benefit over the 400 to 800
polyethylene glycol molecular weight range, but at a relatively
reduced level.
[0053] The unexpected resilient foaming properties of the
formulations of the invention--as measured by the Mini-plate
test--are illustrated in the following examples. It was also
determined that flash foam production was not a reliable predictor
of the Mini-plate detergent performance.
[0054] Foam production, often called flash foaming, of the
formulations in the following examples was measured by methods
well-known in the detergent art. A 100 ml sample of each
formulation at the indicated dilution level was placed in a 500 ml
graduated cylinder at ambient conditions including a room
temperature of about 25.degree. C. Samples were uniformly shaken
and the resulting foam was measured according to the volume of the
foam which appeared above the 100 ml level in the graduated
cylinder.
[0055] The detergency performance effectiveness of each formulation
was measured by the well-known "Miniplate" method wherein a series
of soiled miniature plates (hard surface) are washed in a serial
fashion with a brush in solutions of the hand dishwashing samples
under standard conditions until the distinguishable and
reproducible disappearance of the foam is reached. The standard
conditions included a room temperature of about 25.degree. C. The
number of mini-plates washed is compared to a commercial standard.
The miniplates are soiled with a partially hydrogenated vegetable
oil, available from Procter and Gamble Coompany under the trade
name, Crisco, which was dyed red.
EXAMPLES
[0056] The following examples illustrate liquid cleaning
compositions of the described invention. Unless otherwise
specified, all percentages are by weight. The exemplified
compositions are illustrative only and do not limit the scope of
the invention. Unless otherwise specified, the proportions in the
examples and elsewhere in the specification are by weight.
EXAMPLE I
[0057] Formulations comprising at least two anionic surfactants
were prepared and detergency performance--as measured by the number
of mini-plates washed--was evaluated. In formulations A-F, a first
anionic surfactant comprised a secondary sodium alkane sulfonate
and the co-anionic surfactant comprised an alkyl ether sulfate. All
of these blends contained 37.5 weight percent total surfactant and
contained a ratio of sulfonate to sulfate of about 0.875.
Formulations A-F included coco amidopropyl betaine as a foam
stabilizing surfactant, and ethanol as a hydrotrope as shown in
Table 1. Formulation B-F comprised polyethylene glycol (PEG)
components at a level of about 3.8 wt-% (about 10 percent of total
surfactant) over a molecular weight range from about 400 to about
1500. Foam production as measured in a rotating cylinder test in
water hardness of 150 ppm showed improvement over the base
formulation A for the addition of polyethylene glycol over the full
range of molecular weight. However, the foam production in water
having a hardness of 300 ppm indicated little or no improvement
over the molecular weight range of polyethylene glycol addition in
formulations B-F. As shown in Table 1, and according to the
well-known mini-plate test, the observed number of mini-plates
washed in water having a hardness of either 150 ppm or 300 ppm, all
of the formulations which included polyethylene glycol or PEG (See
columns B-F) exhibited significantly increased detergency
performance in the presence of oily soil. The most significant
increase in Miniplate washing performance occurred in formulation
C, when the molecular weight of the polyethylene glycol was about
600. This enhanced performance extended above a 600 molecular
weight up to about 1000 molecular weight, and then dropped off as
the molecular weight of the polyethylene glycol approached 1500.
The enhanced detergency performance also extended below the
molecular weight value of 600 to about 400. The detergency
performance of the formulations of the present invention is shown
in comparison to the performance of a base blend A, which contains
no PEG. This trend in detergency performance with PEG addition as
measured by foam persistence was indicated by foam generation
results in 150 ppm hardness water but was not indicated by the foam
production results in water with the hardness of 300 ppm.
EXAMPLE II
[0058] Formulation G represented a formulation that included at
least two anionic surfactants, coco amidopropyl betaine and ethanol
(hydrotrope). The ratio of the three surfactants--the two anionic
surfactants and the foam stabilizing surfactant--was maintained at
the level of systems A-F while the total surfactant was increased
by 3.8 percent corresponding to the level of PEG added in systems
B-F. This case can be compared with cases B-E and clearly shows
that without the PEG (400-1000 MW) component, increasing the amount
of total surfactant does not achieve the benefits of the blends
containing PEG and actually reduced the detergency performance at
150 ppm water compared to the base blend, in case A, even though
the foam forming tests indicated that there was a foam production
benefit.
EXAMPLE III
[0059] Formulations H-J, E represented a series of formulations
wherein at least two anionic surfactants, coco amidopropyl betaine,
ethanol (hydrotrope) and the content of 600 molecular weight PEG is
increased from 0.5 to 3.8 weight percent. This series (H-J, E) can
be compared with case A, which contains no PEG, and clearly showed
that the addition of 0.5 percent of PEG provides an increase in
detergency performance (Mini-plate) at the higher water hardness
while at higher PEG levels (1 to 3.8 percent) there is a more
substantial increase in detergency performance shown by the
Mini-plate tests--especially in the water with the greater amount
of hardness--compared to the base blend, A. Conversely, no benefits
are indicated in the foam production at the hardness of 300 ppm,
and the foam production at the 150 ppm level showed a reduction in
benefit with increasing addition of PEG of a 600 molecular
weight.
Example IV
[0060] Another series of formulations (K-M) shown in Table 2 was
developed wherein the formulations included a first anionic
surfactant, secondary sodium alkane sulfonate and a second or
co-anionic surfactant, alkyl ether sulfate, with increasing amounts
of PEG. These systems did not include any additional surfactant.
Formulation K represents a revised base level without PEG and with
the alkane sulfonate and alcohol ether sulfate surfactants. From
formulation K as the new base blend, increasing amounts of a
nominally 600 molecular weight PEG were added at a level of 3.8
wt-% in formulation L and at a level of 5.0 in formulation M, with
the surprising result that the detergency performance shown by the
Mini-plate test at low hardness improved only slightly, while the
detergency performance at the higher hardness value of 300 ppm,
increased significantly over the blend K containing no PEG. The
corresponding foam production tests showed no improvement for the
PEG addition in formulations L and M.
EXAMPLE V
[0061] Formulations N-O shown in Table 2 represented a series of
comparative formulations wherein only one anionic surfactant, alkyl
ether sulfate, was employed with ethanol, and coco amidopropyl
betaine,. Formulation O represented the same formula as N but
contained 3.8 wt-% of 600 molecular weight PEG. In this series
(N-O), formulation N (no PEG) can be compared with formulation O
(3.8 percent PEG) and clearly showed that the addition of PEG at a
level of 3.8 wt-% resulted in a reduction in Mini-plate detergency
performance when only a single anionic surfactant was present. The
foam production in formulation O results were mixed with the foam
production for the 150 ppm water hardness improving slightly, while
the foam production for the 300 ppm hardness decreased relative to
formulation N.
EXAMPLE VI
[0062] Formulations P-Q and R-S shown in Table 2 represented a
series of comparative formulations wherein the total amount of
surfactant was reduced to 10 weight percent and 20 weight percent,
respectively. Formulations P-Q showed that there was no apparent
advantage of adding 3.8 percent PEG to a formulation having only 10
percent total surfactant, even though the ratio of the three
surfactants was the same as case A. Foam production in formulations
P and Q showed little advantage of the PEG addition at this level
of total surfactant. Formulations R-S showed that there was a
significant advantage in Mini-plate detergency performance when the
total surfactant amount was about 20 weight percent in water having
a hardness of 150 ppm, while the increase in detergency performance
at a hardness of 300 ppm was only slight. Foam production in
formulation R was only slightly improved over formulation S.
EXAMPLE VII
[0063] Formulations T-V shown in Table 3 represented a series of
comparative formulations wherein the two anionic surfactants
included secondary sodium alkane sulfonate and alpha olefin
sulfonate together with amine oxide and magnesium sulfate. PEG is
present in formulation U at 2 wt-% and in formulation V at 3 wt-%.
There is no alcohol included. In this series (T-V), the total
amount of surfactant was about 42 wt-%. Both formulations U and V
showed significant detergency performance improvement over
formulation T, demonstrating the unexpected performance benefit
provided by the addition of PEG to a two anionic surfactant system.
Conversely, the foam production results showed a decreased foam
production for increasing PEG addition relative to formulation T,
although there was a slight improvement in foam production in
formulation V relative to formulation T, at the 300 ppm water
hardness level.
EXAMPLE VIII
[0064] Formulations W-Z shown in Table 3 represented a series of
comparative formulations wherein only one anionic surfactant,
secondary sodium alkane sulfonate, is present together with the
foam stabilizing surfactant amine oxide at a total surfactant level
of 42 wt-%. PEG is present in cases X-Z in increasing amounts of 2,
3.8 and 5.0 wt-%. in cases X, Y and Z, respectively. In cases X-Z,
detergency performance decreased with increasing PEG in the
formulation. Foam production results did not show any significant
benefit for the PEG addition. This once again demonstrated the need
for at least two anionic surfactants to achieve the performance
enhancement unexpectedly provided by the PEG.
EXAMPLE IX
[0065] Formulations AA-CC shown in Table 3 represented a series of
comparative formulations which are similar to formulations A, J,
and C wherein the inorganic salt, magnesium sulfate, is present at
a level of about 2 wt-% and ethanol is absent. PEG is present in
cases BB- and CC in increasing amounts of 2, 3.8 wt-%, in cases BB
and CC, respectively. In cases BB and CC, detergency performance
showed an advantage with increasing PEG in the formulations. Foam
production in formulations BB and CC showed significant improvement
relative to formulation AA.
1TABLE 1 DETERGENT BLENDS COMPARATIVE RESULTS Formulation A B C D E
F G H I J Secondary Sodium Alkane Sulfonate 15.4 15.4 15.4 15.4
15.4 15.4 16.9 15.4 15.4 15.4 Alkyl Ether Sulfate 17.6 17.6 17.6
17.6 17.6 17.6 19.4 17.6 17.6 17.6 Coco amidopropyl betaine 4.5 4.5
4.5 4.5 4.5 4.5 5.0 4.5 4.5 4.5 Polyethylene Glycol 400 3.8
Polyethylene Glycol 600 3.8 0.5 1.0 2.0 Polyethylene Glycol 800 3.8
Polyethylene Glycol 1000 3.8 Polyethylene Glycol 1500 3.8 Ethanol
3.81 3.81 3.81 3.81 3.81 3.81 4.2 3.81 3.81 3.81 Water Bal Bal Bal
Bal Bal Bal Bal Bal Bal Bal TOTAL SURFACTANT 37.5 37.5 37.5 37.5
37.5 37.5 37.5 37.5 37 37 Rotating Cylinder (mL Foam @150 ppm) 241
310 368 313 304 310 288 288 275 285 Rotating Cylinder (mL Foam @300
ppm) 220 220 217 177 208 206 256 174 207 222 Mini-Plate (# Plates
Washed @ 150 ppm) 72 87 99 93 72 63 66 69 72 87 Mini-Plate (#
Plates Washed @ 300 ppm) 51 57 72 66 66 48 57 57 63 78
[0066]
2TABLE 2 DETERGENT BLENDS COMPARATIVE RESULTS Formulation A K L M N
O P Q R S Secondary Sodium Alkane Sulfonate 15.4 17.5 17.5 17.5 4.1
4.1 8.2 8.2 Alkyl Ether Sulfate 17.6 17.6 17.6 17.6 33.0 33.0 4.7
4.7 9.4 9.4 Coco amidopropyl betaine 4.5 4.5 4.5 1.2 1.2 2.4 2.4
Polyethylene Glycol 400 Polyethylene Glycol 600 3.8 5.0 3.8 3.8 3.8
Polyethylene Glycol 800 Polyethylene Glycol 1000 Polyethylene
Glycol 1500 Ethanol 3.81 4.3 4.3 4.3 7.10 7.10 1.01 1.01 1.22 1.22
Water Bal Bal Bal Bal Bal Bal Bal Bal Bal Bal TOTAL SURFACTANT 37.5
37.5 37.5 37.5 37.5 37.5 10.0 10.0 20.0 20.0 Rotating Cylinder (mL
Foam @ 150 ppm) 241 378 325 418 329 355 107 84 158 153 Rotating
Cylinder mL Foam @ 300 ppm) 220 215 221 196 313 245 75 73 129 118
Mini-Plate (# Plates Washed @ 150 ppm) 72 63 60 66 84 72 15 15 32.5
20 Mini-Plate (# Plates Washed @ 300 ppm) 51 33 51 57 69 60 12 12
15 12
[0067]
3TABLE 3 DETERGENT BLENDS COMPARATIVE RESULTS Formulation T U V W X
Y Z AA BB CC Secondary Sodium Alkane Sulfonate 11.0 11.0 11.0 31.0
31.0 31.0 31.0 15.4 15.4 15.4 Alpha Olefin Sulfanate 20.0 20.0 20.0
17.6 17.6 17.6 Amine Oxide 11.0 11.0 11.0 11.0 11.0 11.0 11.0 Coco
amidopropyl betaine -- -- -- -- -- -- -- 4.5 4.5 4.5 Magnesium
Sulfate 5.2 5.3 5.4 2.0 2.0 2.0 Polyethylene Glycol 600 0 2 3 2.0
3.8 5.0 2.0 3.8 Water Bal Bal Bal Bal Bal Bal Bal Bal Bal Bal Total
Surfactant 42 42 42 42 42 42 42 42 42 42 Rotating Cylinder (mL Foam
@ 150) 340 299 333 348 328 324 367 265 289 329 Rotating Cylinder
(mL Foam @ 300) 153 132 190 318 334 273 301 197 204 230 Mini-Plate
(# Plates Washed @ 150 ppm) 57 72 75 84 51 75 72 54 69 69
Mini-Plate (# Plates Washed @ 300 ppm) 36 57 63 63 39 66 57 51 60
54
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